v2.4.0.8

Investment in S & I Ophthalmic - Additional Information (Detail) (Subsequent Event [Member], S & I Ophthalmic [Member], USD $) In Thousands, unless otherwise specified	1 Months Ended
	Oct. 31, 2013
Subsequent Event [Member] | S & I Ophthalmic [Member]
Schedule Of Investments In Joint Venture [Line Items]
Initial capital contribution	$ 5,000
Membership interest	50.00%

X

- Definition

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 323

-SubTopic 10

-Section 50

-Paragraph 3

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=6382943&loc=d3e33918-111571

+ Details

Name:	us-gaap_EquityMethodInvestmentOwnershipPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

X

- Definition

The cash outflow associated with the investment in or advances to an entity in which the reporting entity shares control of the entity with another party or group.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 13

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3213-108585

+ Details

Name:	us-gaap_PaymentsToAcquireInterestInJointVenture
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Details

Name:	xon_ScheduleOfInvestmentsInJointVentureLineItems
Namespace Prefix:	xon_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration